ilk by the way of the blood circulation. Such a view has no foundation
in fact as bacteria absorbed into the circulation are practically all
destroyed in the tissues by the action of the body fluids and cells.[23]
While organisms cannot pass readily from the intestine to the udder, yet
this must not be interpreted as indicating that no attention should be
given to the bacterial character of the material consumed. The water
supply given should be pure and wholesome and no decomposed or spoiled
food should be used.

The infection traceable directly to the cow is modified materially by
the conditions under which the animal is kept and the character of the
feed consumed. The nature of the fecal matter is in part dependent upon
the character of the food. The more nitrogenous rations with which
animals are now fed leads to the production of softer fecal discharges
which is more likely to soil the coat of the animal unless care is
taken. The same is true with animals kept on pasture in comparison with
those fed dry fodder.

Stall-fed animals, however, are more likely to have their flanks fouled,
unless special attention is paid to the removal of the manure. All dairy
stalls should be provided with a manure drop which should be cleaned as
frequently as circumstances will permit.

[Illustration: FIG. 9. Showing the bacterial contamination arising from
hair. These hairs were allowed to fall on a sterile gelatin surface. The
adherent bacteria developed readily in this medium, and the number of
bacteria thus introduced into the milk from these hairs can be estimated
by the number of developing colonies.]

The animal herself contributes materially to the quota of germ life
finding its way into the milk through the dislodgment of dust and filth
particles adhering to its hairy coat. The nature of this coat is such as
to favor the retention of these particles. Unless care is taken the
flanks and udder become polluted with fecal matter, which upon drying is
displaced with every movement of the animal. Every hair or dirt particle
so dislodged and finding its way into the milk-pail adds its quota of
organisms to the liquid. This can be readily demonstrated by placing
cow's hairs collected with care on the moist surface of gelatin culture
plates. Almost invariably, bacteria will be found in considerable
numbers adhering to such hairs as is indicated in Fig. 9. Dirt particles
are even richer in germ life. Not only is there the dislodgmen